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Operation / LapTiming

1. AX22 Lap Timing

The AX22 has a function which allows it to store and use lap and track markers. This means that it can calculate the times for sectors and display them directly on the screen or transmit them to a DASH1 or DASH2. The lap timing mode ONLY works under the following conditions

  • AX22 in continuous timing mode
  • CF card inserted with AX22 logging to the memory card
  • GPS locked on to satellites
  • Lap timing enabled in the configuration menu

Lap timing is NOT active during any of the three summary timing modes. Furthermore, lap timing can only operate when the GPS receiver has a lock.

New lap and track marker information will be written to the Compact Flash Card in a .LAP file in the root directory. All of the sector and marker information is stored in the .LAP file. This file can either be generated on the AX22 or from the Analysis software. These two methods of generating the lap markers are discussed here: Manually Adding Track Markers

The lap and track markers are added by pressing the Down button during the continuous timing mode.

When you wish to add track markers, it is advised that you drive slowly round the course that you are on, and press the Down button each time you pass a point you wish to use as a track marker. The first marker you add will ALWAYS be the LAP marker. The markers you subsequently add will split the track up into sectors. It is also worth mentioning that each Marker has a direction to it as well. This means that if you have a hairpin with the two straight-ways fairly close together and you added the track marker as you approach the hairpin, then they will both the approach and exit paths will cross the track marker, but the only time the software will log that you've crossed the track marker is when you have passed the marker in the direction it was added in.

If you missed the addition of a track marker, it is possible to add a marker in after the first lap. The AX22 will calculate where the track marker is in comparison to the track you have drawn so far, and if it is in between two other markers, the hardware will split the sector you are currently in into two, but the track marker will be numbered as the next value.

When you press the Down button to add a track marker, a marker will be added at the next GPS sample point, so it could be up to 0.2 seconds before the marker is actually added. If you are travelling slowly when the marker is added this will have no serious side effects. If you are travelling quickly, it is unlikely you can position the track marker with great accuracy.

1.1 Adding Track Markers from the Analysis software

You can add your own track marker files to the Compact Flash card. The file names MUST be in 8.3 format, this means that the entire file name must be in UPPERCASE letters, and it must have no more than 8 characters before the decimal point and EXACTLY 3 characters as the file extension. The extension MUST also be in UPPERCASE letters. If the files are not named like this, then the AX22 will not be able to recognise them.

To generate a .LAP file from raw data, see the section on Adding Track Markers click here, and add the track markers in the Analysis software, then take this .LAP file and save it to the Compact Flash card. The .LAP files must be placed in the root directory of the Compact Flash card. It is advisable that you have only the .LAP files you need. This will rule out the possibility of the Data Logger Unit picking the wrong file if you have two within close proximity to each other in terms of GPS location.

1.2 Using the Lap Marker files with the AX22

The AX22 stores the lap markers in a .LAP file in the root directory of the Compact Flash card. At the start of a continuous timing mode, the AX22 will check it's current position against the reference positions in any .LAP files on the memory card. As such, you can have 10 different .LAP files on the card, and so long as they were not started with about 15km of each other, the AX22 will pick up the correct one. For this reason, it is very important that the AX22 has a GPS lock at the start of the run, otherwise it will just pick up the first file found. If there are no files on the Compact Flash card, then it will write to the file MARKER01.LAP, if MARKER01.LAP already exists, it will go to MARKER02.LAP, and so on.

Lap Timing Operation

Assuming that you have a lap marker file on the CF card, lap timing operation will start when you pass the start/finish marker for the first time. After this, when you complete each sector, the time will be compared with the time to that point on your fastest lap, and your fastest time for that particular sector. These times will be shown on the screen in the following manner:

S 0:30.62 +0.21
L 0:30.62 +0.19

The top line is sector time information, the bottom line is lap times. In this instance, your sector time was 30.62s which was 0.21 seconds more than your fastest for this sector.

Your time up to this point on the lap was also 30.62s (it must be the first sector on the lap) and this time was 0.19s slower than your time to this point on your fastest lap (I.E. Your fastest sector time for this sector was NOT set on your fastest overall lap)

After the second sector, which was completed in 0:41.53, the display would show the following:

S 0:41.53 -1.00
L 1:12.15 -0.81

This lap timing will continue until the end of the lap, at which time the lap time and sector times will be compared against the previous best ones, the best will be updated as required.

Predictive lap times

With predictive lap timing enabled, instead of the lap times being shown as the time up to that point in the lap, the lap time is extrapolated to estimate the lap time if the rest of the lap was done at the same pace as the fastest lap. So in the above examples. If the best lap time was previously 2:45.23, the first screen would have shown:

S 0:30.62 +0.21
L 2:45.42 +0.19

And the second screen would have shown:

S 0:41.53 -1.00
L 2:44.42 -0.81
Page last modified on January 21, 2015, at 11:05 AM